1. Field of the Invention
The present invention relates to an electric pencil sharpener provided with a vertically movable safety shield element arranged to prevent a pencil from being sharpened when the drawer which accumulates shavings is removed therefrom. A further novel element of the invention is the provision of a positive stop means associated with the cutter assembly gear which provides for a consistent size of pencil points with no burr or defect thereon.
2. Description of the Prior Art
There have been a number of attempts in the prior art to provide for automatic pencil sharpeners whereby the cutter element and the pencil are disengaged from one another or from the motor power source. An example of this is the patent to Meyers, U.S. Pat. No. 864,671 in which when the pencil is completely sharpened to the desired degree a nut has reached its inner travel limit causing disengagement of a detent arm and the return of the cutter and yoke to an initial inactive position.
Another effort at providing an automatic stop electric pencil sharpener is that patent to Uchida, U.S. Pat. No. 3,777,791. In the Uchida patent when a pencil has been shaved to a desired degree the cutter element is adapted to separate away from its engagement with the end portion of the pencil so as to serve as an automatic stop thereby prohibiting unnecessary shaving of the pencil end portion beyond a predetermined degree of sharpness.
The foregoing are illustrative of attempts to provide automatic means by which to stop the sharpening of the pencil within the cutter assembly. In contrast to these devices of the prior art it is a feature of this invention to provide a novel but extremely simple positive stop for a pencil being shaved in the cutter element.
In the instant invention a blade means is disposed transversely of the cutter assembly so that when the cutter bar shifts on its shaft and the cutter bar cuts, zero clearance between the blade and cutter bar is achieved, and the cutter bar cuts into the blade, perhaps by a few thousandths of an inch. When the cutter bar has cut into the stop to a predetermined depth to take up the production tolerance designed therein, the pencil has been sharpened to a fine point. At that stage the blade is in contact with the point of the pencil, and thus the pencil cannot protrude beyond the cutter assembly in this construction so as to allow creation of the burrs normally formed in ordinary pencil sharpeners. The stop is simple, reliable, and does not require operative moving parts so as to displace the cutter mechanism away from the pencil or to shut off the motor.
As regards the safety element, applicant is not aware of any prior art which is pertinent to the examination of this feature of the invention in which a pencil is impeded from entry into the cutter mechanism when the drawer of the pencil sharpener provided for catching shavings is removed from the sharpener.